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Your penis curves to the right or left when erect.

A healthy penis isn't always straight as an arrow. A minor bend or curve is normal. However, a severe bend right, left, up, or down that makes intercourse difficult or impossible requires treatment.

The cause: Peyronie's disease, a condition first described by a French surgeon named Francois de la Peyronie. It happens when a plaque or hard lump forms in the erectile tissue causing the shaft to arc significantly during an erection. The lump is benign, but the bend can be painful and cause permanent scarring, which makes intercourse difficult. (Here's How to Know If Your Penis Curve Is Normal.)

The cure: A doctor injects a medicine called verapamil directly into the plaque to break it down. The most common remedy, however, is surgical. One option is to place two permanent sutures in the lining of the penis opposite the curvature in order to straighten it out. The second, patch coroplasty, is a procedure in which an incision is made through the plaque across the width of the penis to eliminate the pulling that causes the curvature. Then the incision is patched with a skin graft.

There's an agonizing pain in your scrotum.

Possible cause 1: Assuming you weren't just kicked there, one of your testicles is probably twisted around something called the spermatic cord, cutting off the blood supply. "Think of a ball hanging on a rope," says Tony Makhlour, M.D., Ph.D., a urologic surgeon at the University of Minnesota Medical Center. "As the rope turns, it bunches, and the ball rises." This knotting--testicular torsion, it's called--instantly causes sharp pain.

The cure: Head to an E.R. "If it isn't treated within four hours, you can lose a testicle," warns urologist Larry I. Lipshultz, M.S. "Why take a chance?" The docs at the E.R. will do an ultrasound to assess whether your testicle and cord are indeed twisted. If that's the case, a urologic surgeon will be called to untangle things. Then he'll suture each testicle to the inside of your scrotum to prevent the torsion from happening again.

Possible cause 2: Epididymitis. This is an inflammation of the epididymis, the gland at the top of each testicle that collects sperm and transports it to the vas deferens, caused by bacteria. The pain is hard to distinguish from that caused by testicular torsion.

The cure: head to an E.R. for an ultrasound. If it's not torsion, antibiotics will be prescribed to treat the infection and an anti-inflammatory will ease your pain.

It feels like your scrotum is a bag of worms, and your boys are droopier than normal.

The cause: Sometimes the valves inside the veins of the scrotum don't close properly, so blood pools and they swell. The resulting bundle of enlarged veins, or varicoceles, doesn't always hurt, but the extra blood warms the testes. This jeopardizes sperm production (which requires temps cooler than 98.6 degrees Fahrenheit) and causes the testicles to hang away from the body. About 20 percent of men will experience varicoceles at some point.

The cure: "If you notice you have low-hanging fruit, see a urologist who specializes in infertility," says Harry Fisch, M.D., a professor of clinical urology at Weill Cornell Medical College/New York-Presbyterian Hospital and author of The Male Biological Clock. Your doctor can stop blood from pooling by tying off the veins or blocking them. It's minor outpatient surgery and you can have sex again in 3 weeks, although you should schedule a follow-up semen analysis in 3 to 4 months. In 60 percent of infertile men, semen quality will improve after surgery, says Fisch. Even if you're not trying to conceive, he adds, the problem should be corrected if it's painful or creates a size discrepancy between testicles.

You think you broke your penis.

The cause: There are no bones in the penis, so what really happens is a tear in the tissue when the erect penis is bent through some trauma during aggressive sexual activity or masturbation. When the spongy tissue that fills with blood during an erection ruptures, blood escapes the membrane, causing bruising and pain.

The cure: Immediate medical attention is needed to surgically repair the leak or risk deformity or erectile dysfunction.

There's a bulge in your groin area, and it hurts when you bend over, cough, or try to lift heavy stuff.

The cause: You should have hired movers to lift that fridge. Inguinal hernias occur when part of the intestine protrudes through a congenitally weak abdominal wall. "It's often associated with a major straining episode," says Fisch, but a simple sneeze can set it off.

The cure: If it's small and doesn't bother you, no action may be needed. If it's growing or painful, lying down with your pelvis higher than your head can reduce the discomfort, but ultimately you'll need surgery. This will come in the form of either a herniorrhaphy, in which the edges of healthy tissue are sewn together, or the more modern hernioplasty, a laparoscopic surgery technique in which a piece of synthetic mesh is inserted to cover the entire inguinal area. A surgeon will recommend the option best suited to repair your particular type of abdominal-wall tear. You'll be back to work within a few days.

You have pain in your penis, testicles, lower belly, and down your legs, and it hurts when you urinate or ejaculate.

The cause: Chronic pelvic pain syndrome, usually resulting from an inflamed prostate gland. "It's a collection of symptoms that originates from an injury, often an infection, and the problems come from how the body responds to that infection," says Daniel Shoskes, M.D., a Cleveland Clinic urologist.

The cure: Two-thirds of men will get better with antibiotics in the early stages. For those whose inflammation persists beyond initial infection, Shoskes prescribes herbal-based bioflavonoid preparations, such as Prosta-Q and Q-Urol, which reduce inflammation. Flomax and other prescription agents that block an important receptor in the region also reduce pain and can improve urinary flow. Still other men suffer from nerve and muscle spasms, requiring muscle relaxants and physical therapy. See a urologist in any case, but you can help your own cause by taking hot baths; by avoiding alcohol, spicy foods, and caffeine; and by using a doughnut-shaped cushion when sitting for long periods of time. You also shouldn't rule out an STD--like The New Super-STD You Must Avoid.